Inshore Palm Islands

The northern boundary of the Palm Island Inshore reporting zone extends east from the north-west bank of the Seaforth Channel mouth, just south of Hinchinbrook Island, to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.

The southern boundary of the Palm Island zone extends eastward from the southern boundary of the Herbert River Basin to just east of the Palm Island Group and runs north to the Wet Tropics NRM marine region boundary at the junction with the offshore waters boundary.

The major river discharging into the Palm Island zone is the Herbert River. Several sub-catchments, including the Seymour River, also discharge into the Palm Island inshore zone.

Water quality in the Palm Island zone is affected by plumes of sediments, nutrients and pesticides from rivers discharging directly into the zone but also from the plumes of southern rivers, particularly the Burdekin River the mouth of which is approximately 180 km to the south-east.

The area includes the Palm Island group located approximately 17 km east of the mainland. The Palm Island Group includes Orpheus Island, Pelorus Island, Fantome Island, Palm Island, and Havannah Island. These islands provide fringing shallow water environments that support coral reef ecosystems and reef seagrass meadows.

The overall grade for Palm Island zone in 2022-23 improved from ‘moderate’ to ‘good’, and the score increased from 56 to 61 since the previous year.  

Key results

• The water quality grade in 2022-23 for the Palm Island inshore zone remained ‘good’ and scored 75, increasing from 68 in the previous year.
• Improvement in grades since the previous year occurred for oxidised nitrogen (NOx), from ‘good’ to ‘very good’, and for water clarity with both total suspended solids (TSS) and turbidity improving from ‘good’ to ‘very good’.
• Chlorophyll a, declined from ‘good’ to ‘moderate’ since the previous year.
• Pesticide monitoring and reporting re-commenced in 2022-23. High scores and a grade of ‘very good’ for pesticides, due to the very low pesticide toxicity risk, contributed to the increase of the water quality index score.
• The overall score for coral condition in 2022-23 for the Palm Island inshore zone was 47 and the grade remained ‘moderate’. Coral condition in the Palm Island zone has had a ‘moderate’ grade since 2014-15.  
• The grade for coral cover remained ‘moderate’ and the score increased from 47 to 51. The cover of hard coral increased on several reefs since the previous year. Composition improved from ‘moderate’ to ‘good’ due to an increase of score at a single reef. Juvenile coral grade improved from ‘poor’ to ‘moderate’ with an increase in juvenile density occurring at most sites.

The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.